Installing Archlinux on the Macbook5,2 (Polycarbonate, Late 2009) has several pitfalls as of right now. I've written them into this article for people having trouble installing Archlinux on their 5,2 Macbook. This guide assumes you are also going to follow the Macbook install guide, and will point out a few modifications to get it working on this Macbook. Review these suggestions and then follow the guide. This guide also assumes you have rEFIt installed before hand.

Installation

I suggest formatting your Archlinux Partition using a [GParted] live disc, which works just fine. You will more than likely format /dev/sda3 to ext3. You can also use parted from the install disc if you'd like. However, no matter which option you choose, after formatting, you MUST reboot your Macbook and use rEFIt to resync the partition tables.

The Macbook5,2 seems to have trouble in general with Grub (but not grub2). Unless you use the ISOLINUX install disc, you probably won't make it past the grub boot selection screen. Assuming you are using the ISOLINUX disc, boot with:

arch maxcpus=1

Without this, when the installer attempts to initialize the second CPU in your laptop the screen will go blank and you will be unable to proceed. This is a well known issue with the Macbook5,2. You can also boot the system with acpi=off. You will always need one of these options to boot, even after install.

arch acpi=off

Install proceeds normally, except for during hard drive preparation. Manually select block devices, select /dev/sda3 and the filesystem you selected. If you used the Gparted live disc, say that you do not need to create the partition. Ignore warnings about swap drive, That will be handled later. Install should go okay. Do NOT install Grub, it won't work. The next section describes how to use grub2 as your Boot Loader for the Macbook.

Installing Grub 2

Some of this information is pulled from the Grub2 article. As an aside, some triple boot guides suggest using LILO, but I could not get LILO to work.

Ensure the network is properly configured.

From the installer's live shell, chroot to the installed system:

# mount -o bind /dev /mnt/dev
# chroot /mnt bash

Install the GRUB2 package:

# pacman -S grub2

Install GRUB2 to the Archlinux partition (Do not install to /dev/sda!)

# grub-install --recheck /dev/sda3
GRUB2 will probably inform you that this is not a suggested action. However, it is what must be done to boot the system. Use the following to force GRUB2 to install to /dev/sda3
# grub-install --recheck --force /dev/sda3

I found that GRUB2's grub-mkconfig function does not work on the MacBook. I suggest reading the Grub2 article for more advanced tips, but for conveinence, here is my /boot/grub/grub.cfg:

If everything went alright, you should be looking at the command prompt.

Touchpad

The touchpad may not seem to work when you first try X. However, it does. It is just very unresponsive. I suggest preparing the "Advanced Policy Configuration" from the Touchpad Synaptics article. Increase the acceleration, min_speed, and max_speed greatly. Or, wait and use the gsynaptics package to increase them later, and use an external mouse in the interm.